DESCRIPTION

It allows you to validate input via a template. The only requirement is that the arguments must be named.

Params::Check can do the following things for you:

Convert all keys to lowercase

Check if all required arguments have been provided

Set arguments that have not been provided to the default

Weed out arguments that are not supported and warn about them to the user

Validate the arguments given by the user based on strings, regexes, lists or even subroutines

Enforce type integrity if required

Most of Params::Check's power comes from its template, which we'll discuss below:

Template

As you can see in the synopsis, based on your template, the arguments provided will be validated.

The template can take a different set of rules per key that is used.

The following rules are available:

default

This is the default value if none was provided by the user. This is also the type strict_type will look at when checking type integrity (see below).

required

A boolean flag that indicates if this argument was a required argument. If marked as required and not provided, check() will fail.

strict_type

This does a ref() check on the argument provided. The ref of the argument must be the same as the ref of the default value for this check to pass.

This is very useful if you insist on taking an array reference as argument for example.

defined

If this template key is true, enforces that if this key is provided by user input, its value is defined. This just means that the user is not allowed to pass undef as a value for this key and is equivalent to: allow => sub { defined $_[0] && OTHER TESTS }

no_override

This allows you to specify constants in your template. ie, they keys that are not allowed to be altered by the user. It pretty much allows you to keep all your configurable data in one place; the Params::Check template.

store

This allows you to pass a reference to a scalar, in which the data will be stored:

$Params::Check::STRICT_TYPE

This works like the strict_type option you can pass to check, which will turn on strict_type globally for all calls to check.

The default is 0;

$Params::Check::ALLOW_UNKNOWN

If you set this flag, unknown options will still be present in the return value, rather than filtered out. This is useful if your subroutine is only interested in a few arguments, and wants to pass the rest on blindly to perhaps another subroutine.

The default is 0;

$Params::Check::STRIP_LEADING_DASHES

If you set this flag, all keys passed in the following manner:

function( -key => 'val' );

will have their leading dashes stripped.

$Params::Check::NO_DUPLICATES

If set to true, all keys in the template that are marked as to be stored in a scalar, will also be removed from the result set.

Default is false, meaning that when you use store as a template key, check will put it both in the scalar you supplied, as well as in the hashref it returns.

$Params::Check::PRESERVE_CASE

If set to true, Params::Check will no longer convert all keys from the user input to lowercase, but instead expect them to be in the case the template provided. This is useful when you want to use similar keys with different casing in your templates.

Understand that this removes the case-insensitivity feature of this module.

Default is 0;

$Params::Check::ONLY_ALLOW_DEFINED

If set to true, Params::Check will require all values passed to be defined. If you wish to enable this on a 'per key' basis, use the template option defined instead.

Default is 0;

$Params::Check::SANITY_CHECK_TEMPLATE

If set to true, Params::Check will sanity check templates, validating for errors and unknown keys. Although very useful for debugging, this can be somewhat slow in hot-code and large loops.

To disable this check, set this variable to false.

Default is 1;

$Params::Check::WARNINGS_FATAL

If set to true, Params::Check will croak when an error during template validation occurs, rather than return false.

Default is 0;

$Params::Check::CALLER_DEPTH

This global modifies the argument given to caller() by Params::Check::check() and is useful if you have a custom wrapper function around Params::Check::check(). The value must be an integer, indicating the number of wrapper functions inserted between the real function call and Params::Check::check().